Hybrids More Practical Than Pure Electrics

Great interview by Megan McArdle. A lot of people have concluded that gas-electric hybrids make more sense today than pure electrics and so has the market. This is an in-depth explanation of why that is.

A couple days ago, I wrote that taxing carbon wouldn’t necessarily make electric vehicles economically viable. Yesterday, I did an interview with Professor Jeremy Michalek of Carnegie Mellon, who has done research into that very question. The interview has been lightly edited to enhance readability.

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JEREMY MICHALEK: The nice thing about small-battery plug-in hybrid electric vehicles (with gasoline backup) is that the battery is relatively small and can potentially pay for itself in fuel cost savings now or in the near future. These vehicles cost a lot less, so we can buy more of them with a given pool of money, and they are more likely to have sustainable market adoption in the near future.

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Pure battery electric vehicles are far more dependent on future battery prices dropping to low levels, and we don’t yet know if that will happen. Even if it does happen in the future, starting small is likely the best way to get there.

Think of it this way: If you have a 10-mile battery in a plug-in hybrid electric vehicle, then nearly every time you drive the vehicle, you use most of that 10-mile range to displace gasoline. The investment in the battery is well utilized. In contrast, if you have a 40-mile battery, for many shorter trips this investment is nothing but dead weight.

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Looking at all of these together, electric vehicles aren’t necessarily better than today’s gasoline hybrids. Even under optimistic conditions (charging with zero-emissions electricity, assuming the battery lasts the life of the vehicle, etc.) they are only marginally better than hybrids.

MEGAN: And presumably, those optimistic assumptions aren’t particularly realistic: we’re not all going to be charging with our rooftop solar panels or wind turbines.

JEREMY MICHALEK: Exactly. Even if you have a solar panel on your roof, if you charge your vehicle at night (as most of us would), the electricity generated to charge that vehicle will come from coal in many regions. It’s not just about the average electricity in a region – it matters which plants would turn on to meet the extra demand from your plug-in vehicle. In many regions at night, where demand is low, some coal plants turn off. If extra charging demand is added at night, coal plants may be the first to turn back on in response (because they are cheap).

I notice that a lot of EV advocates want to believe that all-electric cars will be charged with green energy – meaning grid-connected hydro, wind, and solar. But there’s no reason to think green energy will charge EVs as opposed to TVs, refrigerators, and hair dryers. There aren’t special power lines carrying windmill power directly to EV chargers.